In Equation (11.2.14) we found that y′0−y0=Fext/k for a spring of spring constant k, where y0 was the old and y′0 the new equilibrium position (the for...In Equation (11.2.14) we found that y′0−y0=Fext/k for a spring of spring constant k, where y0 was the old and y′0 the new equilibrium position (the force was equal to −mg; the displacement of the equilibrium position will be in the direction of the force).